1. Field of the Invention
The present invention relates to a female terminal fitting and to a method of forming or producing it.
2. Description of the Related Art
A female terminal fitting is disclosed in International Publication No. WO 98/29924 and also is identified by the numeral 100 in FIG. 11 herein. The female terminal fitting 100 has a front end and a tube-shaped connecting portion 101 is provided at the front end of the female terminal fitting 100. A resilient contact piece 102 is provided inside the connecting portion 101 for resilient contact with an unillustrated mating male tab. The resilient contact piece 102 has a base at the upper side of the connecting portion 101 and extends back from the base. The resilient contact piece 101 then is curved arcuately down and again extends forward from a rear bottom of the connecting portion 101. However, the resilient contact piece 102 intercepts rays of light propagating in the inner space of the connecting portion 101 along forward and backward directions. As a result, infrared rays cannot measure the space between the resilient contact piece 102 and a contact portion 103 at the upper side. Hence, an improved female terminal fitting with a resilient contact piece has been developed. The improved terminal fitting has a resilient contact piece with a base at the rear side of the bottom surface of a connecting portion and a leading end that extends forward from the base.
Connectors and female terminal fittings have been miniaturized in recent years. Accordingly, the thickness of a metal plate before bending and a tolerance of precision errors in the bending process have been reduced to make the terminal fittings smaller. Small terminal fittings experience problems that terminal fittings of conventional size do not have. For example, the base of the resilient contact piece of the above-described female terminal fitting may be raised slightly by the resilience of the plate when folded at a specified position on the bottom surface. Although such a raised state may cause no problem for a female terminal fitting of conventional size, it may cause the smaller female terminal fitting to deviate from standard technical requirements.
The present invention was developed in view of the above problem and an object thereof is to provide a female terminal fitting in which a base portion of a resilient contact piece can be prevented from being raised even if the female terminal fitting is made smaller.
The invention relates to a female terminal fitting with a connecting portion connectable with a male tab of a mating male terminal fitting. Two contacts are provided on opposed walls of the connecting portion and are adapted to contact and tightly hold the male tab. One of the contacts is on a resilient contact piece configured for resilient contact with the male tab. A lock is substantially between a base of the resilient contact piece and the wall that has the contact to lock the base at a specified position. Accordingly, the resilient contact piece cannot be raised, and the female terminal fitting fulfills standard technical requirements even if the terminal fitting is small.
The connecting portion is substantially tubular, and hence can be inspected by light passing through the connecting portion.
The resilient contact piece preferably extends from the wall that faces the wall that has the other contact portion.
The connecting portion can be formed into the shape of a tube, for example, a rectangular tube or a cylindrical tube.
The base of the resilient contact piece may be provided at either the front side or the rear side in the connecting portion. Thus, the resilient contact piece may extend backward from the front side of the connecting portion or forward from the rear side of the connecting portion.
The locking construction may take any construction that positions the base of the resilient contact piece. Specifically, a cut may be made in a portion of the wall of the connecting portion, and the cut portion may be folded to bring the inner surface thereof into contact with the upper surface of the base. Alternatively a side edge of the base may partially serve as an engaging edge, and a locking hole may be formed in the wall for receiving the engaging edge.
Accordingly, the locking construction between the base and the wall positions the base of the resilient contact piece and prevents the base of the resilient contact piece from being raised. Thus, the female terminal fitting can fulfill standard technical requirements even if the terminal fitting is made small.
The locking construction preferably comprises an engaging edge that projects from a side edge of the base and a locking hole formed in the wall for receiving the engaging edge. Accordingly, the engaging edge that projects from the base fits into the locking hole in the wall during the bending of the female terminal fitting, thereby positioning the base of the resilient contact piece. Therefore, less labor is required as compared, for example, to a case where a cut is made in the wall and the cut portion is bent to bring the inner surface thereof into contact with the upper surface of the base.
The locking hole preferably is on a border of the wall adjacent to a lateral wall that is bent at an angle with respect to the wall portion.
Most preferably, the resilient contact piece projects in towards a mating side of the female terminal fitting with the male tab from its base.
The invention also relates to a method for forming a female terminal fitting. The method comprises providing a conductive plate, and stamping and bending the conductive plate to form a connecting portion with opposed facing walls. Two contacts are provided on the facing walls of the connecting portion. One of the contacts is provided on a resilient contact piece for resilient contact with the male tab. The walls are bent so that a lock is positioned substantially between a base of the resilient contact piece and the wall that has the contact locks the base at a specified position.
According to a preferred embodiment of the invention, the connecting portion is formed to be substantially tube-shaped.
Preferably, the resilient contact piece is formed to extend from the wall substantially facing the wall that has the other contact portion.
The locking construction preferably comprises an engaging edge that projects from a side edge of the base and a locking hole in the wall wherein the engaging edge is fitted into the locking hole when bending the walls. The locking hole preferably is formed on a border of the wall adjacent to a lateral wall that is bent at an angle with respect to the wall.
A cut preferably is made in a portion of the wall of the connecting portion for forming the lock. The cut is folded to bring the inner surface thereof into contact with the upper surface of the base, and a side edge of the base partially projects to serve as the engaging edge. The locking hole for receiving the engaging edge is provided in the wall.
The resilient contact piece preferably is formed to project in towards a mating side of the female terminal fitting with the male tab from its base.
These and other objects, features and advantages of the present invention will become more apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are separately described, single features thereof may be combined to additional embodiments.